Problems with running OpenSesame on MacOS Mojave

We have recently received many reports that OpenSesame does not run smoothly any longer on the latest MacOS version 10.14: Mojave. I've looked into some of the issues and can tell you the following:

The expyriment and psychopy backend do not work well, because Apple has deprecated (or dropped support for) OpenGL from MacOS Mojave onwards. OpenGL is the 'system' that is used to draw all stimuli to the screen, and both Expyriment and Psychopy heavily rely on it. Apple dropped OpenGL in favor of their own system Metal, so it doesn't look like proper official support for OpenGL will return anytime soon, unless it is picked up by the community. There appear to be some workarounds to fix the current issues, but we depend on the developers of Expyriment and Psychopy to solve these before they work in OpenSesame again.

Many issues with the GUI of OpenSesame are hopefully fixed by an update of the PyQT library, which OpenSesame uses to build its interface. We hope to include an updated version of PyQT in the next version of OpenSesame for Mac.

For now, I advise against using MacOS for running experiments. You can still create or build the experiments on MacOS, and test them using the legacy backend, which should still work. This backend however does not provide a reliable timing when collecting responses or displaying stimuli, so it's unwise to run real experiments with it.